1. Field of the Invention
The present invention relates to radio controlled timepieces and more particularly to their housing structures.
2. Description of the Background Art
Radio controlled timepieces are known which include an antenna structure which receives standard radio waves including time information to set a current time automatically based on the received radio waves. As the antenna structure, antennas are widely used which include a bar shaped core made of a magnetic material with high reception sensitivity such as an amorphous metal or ferrite, and a coil wound around the core.
With such timepiece, if there are metal members near the antenna structure, magnetic flux produced in the antenna structure due to received radio waves passes these metal members, thereby producing eddy currents, winch brings about an eddy current loss and reduces reception sensitivity.
Recently, the housing (or case and bottom cover) of the timepiece is made of a metal material such as titanium or stainless steel to produce an excellent design and a sense of high quality in addition to functionality. Even when the antenna structure is disposed within such a metal housing, it is required for such timepiece to have enough reception sensitivity.